December weather forecast
Castana, IA

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Weather in December

December, the first month of the winter in Castana, is still a cold month, with an average temperature fluctuating between 32.2°F (0.1°C) and 20.3°F (-6.5°C).

Temperature

Castana's weather undergoes a significant change with the arrival of December, as the average high-temperature drops from a frosty 47.3°F (8.5°C) in November to a wintry 32.2°F (0.1°C). An average nighttime temperature of 20.3°F (-6.5°C) is observed during December.

Humidity

In Castana, the average relative humidity in December is 79%.

Rainfall

In Castana, in December, during 3.5 rainfall days, 1.42" (36mm) of precipitation is typically accumulated. Throughout the year, there are 117.6 rainfall days, and 21.89" (556mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Castana are January through April, October through December. In December, it is snowing for 7 days. Throughout December, 2.13" (54mm) of snow is accumulated. Throughout the year, there are 32.9 snowfall days, and 11.69" (297mm) of snow is accumulated.

Daylight

December has the shortest days of the year, with an average of 9h and 12min of daylight.
On the first day of December, sunrise is at 7:33 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:51 am and sunset at 5:02 pm CST.

Sunshine

In December, the average sunshine in Castana is 4.9h.

UV index

February and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, the maximum UV index of 1 suggests this advice:
Apart from children, who require continuous protection, most can endure sun exposure for up to an hour without experiencing burns. Minimize direct exposure to the Sun during midday when its radiation is at its peak. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
Updated: Jul 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

The average high-temperature, in December, in Castana, is 32.2°F (0.1°C), while the average low-temperature is 20.3°F (-6.5°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines relative humidity and air temperature, in August is calculated to be 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 79%.

How many days does it rain in December?

In December, the rain falls for 3.5 days. Throughout December, 1.42" (36mm) of precipitation is accumulated.

How much does it snow in December?

In Castana, in December, during 7 snowfall days, 2.13" (54mm) of snow is typically accumulated.

What is the month with the shortest days?

With an average of 9h and 12min of daylight, December has the shortest days of the year.

How many hours of daylight does Castana have in December?

In December, the average day length is 9h and 10min.

When is the sunrise / sunset in December?

On the first day of December in Castana, sunrise is at 7:33 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:51 am and sunset at 5:02 pm CST.

How long on average sun shines in December?

The average sunshine duration in December is 4.9h.

What is the month with the lowest UV index?

The months with the lowest UV index are February and December, with an average maximum UV index of 1.

What is the UV index reading in December?

In Castana, the average daily maximum UV index in December is 1. A UV Index estimate of 2, and below, represents a low health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Castana, IA

Average temperature in December - Castana, IA
  • Average high temperature in December: 32.2°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (28°F).

  • Average low temperature in December: 20.3°F

The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).

Average pressure in December
Castana, IA

Average pressure in December - Castana, IA
  • Average pressure in December: 30.13"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

Average wind speed in December
Castana, IA

Average wind speed in December - Castana, IA
  • Average wind speed in December: 10mph

The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest month (with the lowest average wind speed) is July (7.4mph).

Average humidity in December
Castana, IA

Average humidity in December - Castana, IA
  • Average humidity in December: 79%

The month with the highest relative humidity is January (82%).
The months with the lowest relative humidity are April and October (66%).

Average rainfall in December
Castana, IA

Average rainfall in December - Castana, IA
  • Average rainfall in December: 1.42"

The wettest month (with the highest rainfall) is May (3.31").
The driest month (with the least rainfall) is January (0.67").

Average rainfall days in December
Castana, IA

Average rainfall days in December - Castana, IA
  • Average rainfall days in December: 3.5 days

The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is February (2.7 days).

Average snowfall in December
Castana, IA

Average snowfall in December - Castana, IA
  • Average snowfall in December: 2.13"

The month with the highest snowfall is February (3.03").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in December
Castana, IA

Average snowfall days in December - Castana, IA
  • Average snowfall days in December: 7 days

The month with the highest number of snowfall days is January (8.9 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
Castana, IA

Average daylight in December / Average sunshine in December - Castana, IA
  • Average daylight in December: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in December: 4h and 5min

The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in December
Castana, IA

Average sunshine days in December - Castana, IA
  • Average sunshine days in December: 20.7 days

The month with the most sunshine days is November (21.5 days).
The month with the least sunshine days is June (12 days).

Average UV index in December
Castana, IA

Average UV index in December - Castana, IA
  • Average UV index in December: 1

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are February and December (UV index 1).

Average cloud cover in December
Castana, IA

Average cloud cover in December - Castana, IA
  • Average cloud cover in December: 48

The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 26).

Average visibility in December
Castana, IA

Average visibility in December - Castana, IA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Castana, Iowa, USA

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